The purpose of this project is to begin a systematic evaluation of pharmacological agents which are of theoretical significance for the etiology of age-related cognitive impairment, and which are of potential value for treatment of senility. Since 10% of the 30 million elderly suffer from significant cognitive decline, this represents a major public health problem. As a first step in an overall program to examine the possible role of devrease in central neurotransmitter availability in the etiology of abnormal cognitive decline, the specific hypothesis to be evaluated in this project is that decreased availability of acetylcholine is related to senility. If this hypothesis is correct, it follows that agents which increase brain acetylcholine should improve the cognitive impairment of geriatric patients. This prediction will be tested by evaluating choline in a placebo-controlled, double-blind crossover study. Since there is evidence that 1-Dopa may improve cognitive function, this drug will also be evaluated in order to test the specificity of the cholinergic system for cognitive impairment. There will be 60 cognitively impaired outpatients (ages 60-85) in each of the two studies. The patients will be randomly assigned to one of the 6 active-drug or placebo groups. The duration of the study will be 16 weeks (a 2-week washout, followed by a 6-week drug or placebo period. This will be followed by another 2-week washout and a 6-week drug or placebo period). A cognitive test battery, behavioral rating scales, and physiological measures (including computer analyzed EEG) will be administered weekly or biweekly in order to assess treatment effects. If the results substantiate the hypothesis of reduced availability of acetylcholine in senility, it will be feasible to treat senility using agents which increase brain acetylcholine.